Without fuel, the engine does not work, and without the engine, everything else.
Many car owners, it happens, do not even know that their cars are designed with such an electric fuel supply device, located either in the tank or not far from it, and if they know about it, then only in theory.
A gasoline pump can seriously think about itself when a car suddenly stands up with a stake in the middle of the road in an open field. There is gasoline, oil is normal, there is a spark, but the car does not run.
This is where questions and searches for reasons begin.
The prerequisites for suspecting an electric petrol pump of a malfunction can be the following phenomena:
1) power loss,
2) the car does not start well even on a warm engine,
3) the engine stalls, troit, moves in jerks at a constant speed, idle speed "floats".
4) noise, hum, buzz, creak, whistle emanating from the tank (with a submersible pump) or from under the bottom of the body (with an outboard pump)
In order about each item:
Loss of power.
The thing is that the fuel pump - although it does not belong to consumables such as a filter or tires, however, has its own margin of safety. The car manufacturer takes this fact into account and creates a gas pump that presses when the voltage on the pump is 12 volts, for example 8 bar, although the pump has a relief valve that relieves excess pressure and is triggered at 5 bars. Time passes and the pump ages; at the same voltage, the pump can already deliver a maximum of 6 bar, and so on. Problems with the loss of engine power arise when the maximum pump pressure is lower than that required in the fuel system for normal operation of the fuel equipment after the pump (overcoming the resistance of the fuel fine filter, triggering injectors, etc., etc.). That, in general, leads to an undersupply of gasoline for the engine, and as a result, a drop in power.
Bad to start.
A car can start poorly for various reasons, but why one of them can be a malfunction of the fuel pump? For normal engine operation, a certain pressure in the fuel system is required. Ideally, after the engine is turned off, the pressure is maintained in the fuel system, and when the ignition is turned on, the pump pumps fuel into the system to start. However, with wear and tear, there are cases when the pump creates the required pressure for a longer period of time, and the valve does not hold the pressure in the system as it should. As a result, the car will not start well.
In some cases, the car may start after the car has stood for a while, although before that it stalled and stubbornly did not start. This may indicate that the grid of the gasoline pump is clogged, or something prevents gasoline from normally entering the flask, from where the pump pumps it.
If the car starts up every other time, or even after knocking on the pump, the fuel pump anchor or graphite brushes are most likely worn out. You should not change them on your own, because even after successfully flaring, removing the pump internals, replacing the brushes with new ones, rolling the pump, it will not work for a long time, since the graphite from a simple electric drill will be erased in a month, if not in a week, or will destroy the anchor of the gas pump, being of the wrong hardness, without the necessary additives, in gasoline.
Incorrect engine operation
The engine runs intermittently or stalls - the problems are the same as in the previous paragraphs: the grid is clogged, or the pump is faulty. Sometimes there are wiring problems: the current simply does not reach the pump, or as a result of poor contact, the terminals on the pump will spark, etc.
There are also many reasons for failure, among them the most popular are:
1) Riding on a "dry" tank
2) The work of the fuel pump when driving on gas
3) Contamination of the filter (mesh) of the fuel pump to the state of "vacuum packing", or even violation of mechanical integrity.
4) Water in the tank
5) Dirt / rust / debris in the tank
6) Jamming of the pump impeller / rollers with foreign objects in the tank.
7) Wear of the pump armature / brushes
8) Deformation of the tank and, as a consequence, destruction of the pump / pump module.
9) Normal wear and tear.
10) Handicraft installation / removal of the fuel pump "Indians"
And so, in order:
When driving on an empty tank, the fuel pump heats up. This fact is at least obvious from the fact that gasoline is the only thing that surrounds the pump and cools it, and the only thing passing through it lubricates it. In the absence of gasoline or an insufficient amount of it, the pump heats up for two reasons: firstly, the mechanical friction of the fuel pump units, and secondly, because of the direct current passing through the pump (3-12 amperes). As a result, the pump heats up, the gaps between the rubbing parts decrease from thermal expansion, and as a result, a completely new pump may stop, and if the fuse does not blow out, it will work like a boiler in the tank until the pump housing, pump module, and other adjacent elements are melted, until contact between the terminals is lost fuel pump.
When driving on gas, the increased injury rate of the pump depends, as in the above paragraph, on the presence of gasoline in the tank.
Car owners who have gone to gas have a habit of forgetting about gasoline without using it, and often the pump, without shutting down, pumps gasoline from the tank (if there is still gas there) to the fuel rail to the engine, and since a car running on gas is already hot from the hot rail gasoline goes back to the pump, usually into the pump flask, which adds fuel to the fire, contributing to heating.
If the mesh is blocked, a perfectly normal pump can break in a matter of days. The pump grid, being clogged, does not allow gasoline to flow in the required amount.
Everything is not so scary and difficult if you do not ignore it. The clogged mesh can be cleaned, changed, and most likely this can help the car drive normally, and the car owner can save money on repair or replacement of the pump. Sometimes the car loses insignificantly in power, and then suddenly the symptom disappears - it is possible that the mesh was clogged and rubbed in the tank until such holes are formed, which are equivalent to the absence of the mesh. This threatens that everything that can only gets into the pump and breaks down the latter.
Water in the tank. Although gasoline is slightly soluble in water (0.001-0.004%), there are cases of water getting into the tank. This happens when refueling with low-quality fuel (it is even possible to refuel with emulsion of water and gasoline after a recent visit of a fuel truck to refueling), and during the natural process of condensation of atmospheric moisture inside the tank due to temperature differences. Water corrodes the tank, and being heavier than gasoline, it collects other particles from the bottom of the tank, wetting them and carrying them away.
Water has a detrimental effect on the fuel pump and injector nozzles. If water gets into the fuel lines in winter, it can simply freeze and create a plug that simply won't start the engine.
Dirt / rust / debris in the tank
Dirt usually enters the tank in the same way as water - namely, filling with low-quality fuel, but sometimes it ends up there after using special fuel with additives, or the actual additives. The fact is that after the ingress of special substances intended to dissolve the mud on the walls of the tank, the plaque, being dense enough, does not dissolve, but flakes off the walls of the tank in flakes, filling up the grid of the gasoline pump. Also, such additives can contribute to the corrosion of the tank, with the participation of water, which leads to the appearance of rust, up to the loss of the tightness of the tank.
Jamming of the pump impeller / rollers by foreign objects that have got into the tank usually occurs if the fuel pump mesh has lost its integrity.
The wear of the pump armature / brushes usually occurs when driving without gasoline (gas) or when it is on the bottom of the tank. Gasoline, being the only lubricant, lubricates the rubbing surfaces of the armature and brushes. Under inadequate operating conditions, the brush mechanism fails within two to three months.
Deformation of the tank and, as a result, destruction of the pump / pump module is a rare phenomenon, but it still happens. The most commonplace way is to catch a bump, a hole, hitting the tank, from which the insides of the latter become unusable, however, it happens that the car simply stops driving, when the tank lid is opened, a whistle of air sucked into the tank is heard, and the tank turns out to be flattened when viewed. Reason: the adsorber of gasoline vapors is clogged, due to which air did not enter the tank. This is because with a full tank of gasoline there is not much air left there, and as the fuel is consumed, its place is taken by air passing through the adsorber, and if something is wrong with the "air release", then the pump, pumping out the fuel from the tank, creates a reduced pressure in the tank, from which it can flatten, and the vacuum can reach such degrees that the pump is no longer able to suck in fuel and supply it to the engine.
Natural wear of the pump is inevitable, but it is very accelerated when abrasive - sand, fine metal chips, etc., gets into the impeller / roller mechanism.
The armature-brush mechanism remains in excellent condition, the current consumption is within the normal range, and an increase in the gaps between the rubbing parts leads to a loss of performance and a decrease in pressure in the fuel system.
And finally, a few words about what a makeshift installation / removal of a gasoline pump by "Indians" is.
There are many reasons and breakdowns during the invasion of an inexperienced and ignorant into the fuel supply system, but over more than a dozen years of practice in repairing and replacing gasoline pumps, an idea has formed, thanks to which 4 groups of human factor influence on a fuel pump malfunction and its abnormal operation can be distinguished:
- installation of a non-native pump. (For example, on a Passat from a VAZ, etc.)
- installation of a pump without a grid.
- incorrect installation of the pump, pump module, mesh.
- installation of the pump without special tools.
Read more about "Indians" in the next article.
By itself, gasoline (diesel fuel) from the car's tank will not be able to get into the engine, for this you need a pumping mechanism - a fuel pump. And if it breaks down, it is not difficult to predict the consequences - the car will stop. There can be many possible reasons for this, and since they are typical for almost any car brand, it is better to talk about them using a specific example. Let's say that the VAZ-2110 gas pump is not working.
Types of fuel pumps
Serial production of "dozens" began in 1995, that is, at a time when domestic cars were still equipped with carburetor systems. In them, for pumping fuel, gasoline pumps (pumps) of a mechanical type were installed. Such a pump functions directly from the car engine.
For proper operation of the carburetor, high pressure is not required, and therefore the pump has a relatively simple design, similar to water pumping systems. It is installed directly under the hood of the car, which certainly makes it easier to maintain or replace.
With the advent of injectors, the design of the gas pump was also modified, it became electric. The principle of its operation has also changed. If for the operation of a mechanical pump it is required that the starter begins to rotate the crankshaft, then the fuel pump is first fed in the injection system, which, with the help of a built-in electric motor, creates the required pressure in the line, and only after that the engine starts.
This type of fuel pump is installed directly into the fuel tank.
Thus, there are two types of fuel pumps: mechanical and electrical.
The gas pump does not work: signs of breakdown
Regardless of the design of the engine, if the gas pump fails, the symptoms of its breakdown for both types appear the same, and they manifest themselves as follows:
- If the spark plugs are in good working order, the spark is good, the engine turns, but there are no flashes in the cylinders.
- There are occasional flashes in the engine cylinders, but the engine will not start.
- The engine starts, but at the same time the revolutions "float".
- The engine starts, idle speed is normal, but when you try to increase it or start moving, the engine stalls.
- While driving, the car twitches, when you try to raise the revs, dips in the engine are felt, the dynamics of the car decreases (does not pull).
It is worth noting that similar symptoms can appear in other breakdowns, for example, with a heavily soiled fine filter, a faulty mass air flow sensor (air flow sensor) or clogged nozzles. Therefore, the fuel pump cannot be blamed for these symptoms.
In injection vehicles, when the ignition is turned on, a buzz is heard from under the rear seat, this turns on an electric motor that pumps fuel, if there is no sound, then the gas pump does not work.
The mechanical fuel pump failed: what are the reasons?
There may be several reasons why the VAZ-2110 gas pump does not work:
The electric fuel pump does not work, possible causes of the breakdown
In an injection engine, the fuel pump operates from the vehicle's on-board electrical network, so its failure is not always associated with a breakdown of the pumping mechanism itself. The cause of a malfunction may also be: a failed fuse, relay or oxidation, burning of the contacts on the wires supplying the electric motor.
Another common reason why the VAZ-injector fuel pump does not work may be a mesh filter installed at its inlet. Despite the fact that it is intended for the initial, coarse cleaning of fuel, its mesh has a rather dense structure. And since the pump is in the tank, it practically touches its bottom and the sediment accumulating there, which contaminates it.
Well, the worst thing is a breakdown of the motor, which is responsible for the circulation of gasoline inside the pump, or the failure of its structural elements.
Methods for checking the fuel pump
It is very simple to find out whether a mechanical gas pump is working or not, for this it is enough to disconnect the end of the hose connecting the pump to the carburetor, and, lowering it into an empty bottle, press the manual priming lever located on the pump several times. At the same time, gasoline should flow out of the hose in a pulsating stream. This will allow you to find out if the internal elements of the pump are working properly or not.
To understand why the fuel pump does not work on an injection engine, you first need to "ring" its electrical circuit. It is better to start the check from the end point, that is, from the pump itself. A control lamp is connected to its terminals, and if it lights up with a turn of the key in the ignition lock, then everything is in order with the electrician, the breakdown must be looked for in the pump itself, if not, then in the fuse, relay or in the wiring.
To check the fuel pump itself, you need to find out what pressure it creates in the fuel rail:
- At idle, its value should be in the range of 0.23-0.25 kPa.
- When starting the motor - 0.3 kPa.
- When you press the accelerator - 0.28-0.3 kPa.
- When pinching the return pipe that returns excess gasoline to the tank, the pressure should rise to 0.4 kPa.
If in any of the modes the pressure does not correspond to the norm, therefore, the gas pump does not work as it should - its elements are badly worn out and require repair or replacement.
Trouble-shooting
To repair a mechanical fuel pump, you will need to purchase a repair kit, which includes a diaphragm and valves - you can change these parts yourself. Also, replacing a pusher with a spring will not be difficult. If the breakdown is more serious, then the point in resuscitation disappears, it will be cheaper and easier to install a new fuel pump.
An electric fuel pump has a non-separable body, and it is not worth trying to repair it without having certain skills, it is better to entrust this work to specialists. The only thing that you can do yourself is to replace the mesh of the internal coarse filter. But here you need to know that there are different types of nets, so you have to remove the filter from the tank to get a sample.
Fuel pump breakdown prevention
To extend the life of the fuel pump, you need:
- Monitor the quality of the fuel filled into the car.
- Completely exclude even the possibility of water getting into the tank.
- During scheduled maintenance, it is imperative to change the fuel filters.
- In case of mechanical damage to the fuel tank, it is necessary to dismantle the fuel pump and check its condition.
- Periodically clean the fuel tank from possible accumulation of sediment, consisting of the smallest solid particles contained in gasoline.
Following these simple rules will have a beneficial effect not only on the fuel system, but also on the engine itself.
An automobile gasoline pump is a device designed for uninterrupted supply of fuel to the installation in which the fuel mixture is formed. Even the slightest malfunction of it leads to interruptions in the operation of the engine, and in case of more serious problems, you simply will not start it.
In this article, we will consider situations when the gas pump does not pump fuel at all, or it pumps, but not in the amount that the power unit needs for normal operation. We will also try to understand the possible causes of a particular malfunction of the fuel supply device and discuss methods for their self-elimination using the example of domestically produced cars, the carburetor VAZ-2109 and the injection VAZ-2114.
What are gas pumps
Cars with gasoline engines, depending on the brand, model and modification, can be equipped with gasoline pumps of different design. But they all fall into two main categories: mechanical and electrical. Most are equipped with mechanical fuel delivery devices. If we take (the carburetor), then from the factory it was completed with the production of DAAZ. The main difference between this device is its simplicity of design, which is easy to understand even for a beginner. In the carburetor "nine", the fuel pump is located in the engine compartment of the car. It is easy to recognize by its characteristic hemispherical cap and fuel line hoses.
VAZ 2114 injection engines are equipped with electric fuel pumps. Their design is also based on a membrane, but unlike the "mechanics", the fuel supply devices in cars with automatic fuel injection are not under the hood, but directly in the tank.
Signs of a malfunction of the fuel pump
Whichever engine your vehicle is equipped with, there are similar signs that something is wrong with the fuel delivery device. These include:
- Lack of engine response to starting attempts.
- Violation of the stability of the power unit at idle.
- Troenie.
- Decrease in power.
The design of the fuel pump of the carburetor VAZ 2109
To understand why (carburetor) does not pump, let's take a quick look at its design. So, the fuel supply device "nine" consists of:
- hulls;
- a pusher with a mechanical pump lever;
- diaphragm assembly;
- covers with valves and fittings for fastening hoses;
- mesh filter;
- the manual pumping lever.
The principle of operation of a mechanical fuel pump
The fuel pump is driven by a camshaft cam that moves the pusher horizontally, causing it to reciprocate. The pusher, in turn, acts on the mechanical pumping lever, and it already raises and lowers the diaphragm rod.
Thus, a certain pressure is created inside, which is maintained by the valves of the cover of the device. One of them passes the fuel inside, not letting it back in, and the second pushes it into the fuel line leading to the carburetor.
As you can see, the design is very simple, therefore, in order to determine the reason that the gas pump does not pump, it is enough to disassemble it and check the condition of the main elements.
Pusher
Since the body does not affect the operation of the gas pump in any way, if, of course, it is not damaged, then we will start with the pusher. This element is made of steel and cannot break just like that. But to wear out - please, especially if it is not original, but purchased as a separate spare part. As soon as its length is reduced by a few millimeters, the fuel pump does not pump fuel.
Rather, it shakes, but the amplitude of movement of the diaphragm is significantly reduced. Hence, the low pressure of the fuel in the system, and, as a result, interruptions in the operation of the engine. The standard length of the pusher for DAAZ pumps is 84 mm. Measure its length and replace the worn part if necessary.
Diaphragm
The most common diaphragm failure is rupture. It also happens that it is deformed. Due to this damage, the diaphragm begins to pass fuel through itself, which also causes a drop in pressure in the system.
It is possible to detect such a malfunction only by disassembling the fuel supply device. If the diaphragm is to blame for the fact that the gas pump does not pump, you will immediately see it. This problem is solved by replacing it.
Cover with valves and fittings
Since you have disassembled the fuel pump, do not be too lazy to check the valves. One of them must let the fuel in and the other must let out. Just blow them out and see how well they work. If the valves do not cope with their tasks, replace the cover assembly.
Pump filter and manual priming lever
The first thing you will see when you disassemble the fuel supply is a strainer. It is made of thin perforated plastic. The reason is that the gas pump does not pump, it can also serve if it is deformed or severely contaminated.
In the first case, the filter must be replaced; in the second, it must be rinsed with a carburetor cleaner.
The manual pumping lever has nothing to do with the fact that the gasoline pump does not pump fuel when the camshaft rotates. The only thing that can break in it is the spring that pushes it back to its initial position.
The fuel pump does not pump: the injector
As already mentioned, pumps in carburetor and injection engines have different designs. In cars with forced injection of fuel, all processes associated with its supply to the combustion chambers are controlled by an electronic control unit, so breakdowns of various kinds of electronic devices can occur here.
The main reasons why the fuel pump of an injection engine does not pump include:
- malfunction of the electric drive of the device;
- clogged pump filter;
- failure of the relay;
- blown fuse.
How to understand that it is the gas pump that is the cause of engine interruptions
Diagnosing problems with a gasoline pump in a car with an injection engine is much easier than in a car with a carburetor engine. The fact is that when the ignition is turned on, the sound of the fuel module electric motor is clearly heard. It continues for several seconds. This sound indicates that the fuel pump is spinning and pumping fuel.
If this happens when you turn the key, then everything is in order with the device itself, and the reason must be looked for elsewhere. Well, if, when you turn on the ignition, you do not hear the characteristic sound of the pump operation, you can be sure that the problem is in it, or in the elements of its energy supply.
Start with a relay and fuse
Considering that the fuel supply module is located in the car's tank, and it is not so easy to get to it, it is better to start diagnostics with a relay and a fuse:
- Remove the screws securing the cover located to the left of the steering column.
- Find fuse F3 (15 A) and relay R2 under it. These are the elements that we need to check.
- As for the fuse, it is necessary to "ring" it with a tester. If unsuitable, replace it.
It is quite difficult to check the relay in a garage. But you can take a similar (from an adjacent socket), known to be good relay, and put it instead of the diagnosed one. Now turn on the ignition. Is the gas pump pumping? Reason found! Well, if nothing has changed, let's move on.
Electric drive and filter
The fuel pump in the VAZ 2114 engine is an element of the fuel module, which is located in the car's tank. It also includes:
- coarse filter;
- fuel level sensor;
- branch pipes for connection to the fuel line.
To get to the module, it is necessary to remove the lower part of the rear seat, disconnect the wiring harness and unscrew the 8 screws securing its cover. Remove the entire device assembly. First of all, inspect the coarse filter. If it is clogged, replace it.
To test the electric motor, you will need to connect it directly to the battery terminals. In case of its normal operation, "ring" the wiring and check the contact of the ground wire on the module cover. If the electric motor does not show signs of life, the question "why does not the fuel pump pump" has finally found its solution.
Trying to repair it yourself is impractical. Just buy a new motor and replace the old one. And yet, do not spend money on the purchase of the entire module, which now costs about 3 thousand rubles. Buy separately an electric motor and a new filter. All this will cost you three times less.
